I. Field
The present invention pertains generally to the field of communications and more specifically to a novel and improved system and method for allocating a plurality of data streams onto a single channel given transmission time interval (TTI) constraints.
II. Background
A remote station is located within a network. The remote station includes applications that produce data streams. The remote station allocates the data streams onto a single data stream. A technique for multiplexing data from data streams onto a single data stream is disclosed in U.S. application Ser. No. 09/612,825, filed Jul. 7, 2000, entitled xe2x80x9cMETHOD AND APPARATUS FOR PROPORTIONATELY MULTIPLEXING DATA STREAMS ONTO ONE DATA STREAM,xe2x80x9d which is assigned to the assignee of the present invention and incorporated by reference herein.
Choosing an allocation scheme for allocating bits from multiple data streams onto a single channel is difficult because a number of factors have to be taken into consideration. One factor that has to be considered is the priority of each data stream. Higher priority data streams take precedence over lower priority data streams. Another factor that has to be considered is the transport format combinations (TFCs) that are allowed to be transmitted over a channel. A TFC is a combination of transport formats (TFs), each transport format corresponding to a transport channel. A transport format has a number of blocks (i.e. one or more blocks) of data and a block size (BS). The TFC is sent out on a wireless link of the remote station. Yet another factor that has to be considered is transmission time interval (TTI) constraints. Each transport format has a transmission time interval and cannot change during its transmission time interval. An allocation scheme that takes into consideration the priority of data streams, the TFCs available, and the TTIs of the TFs in the TFCs is desired.
The presently disclosed method and apparatus are directed to allocating a plurality of data streams onto one data stream for transmission. A list of allowable TFCs is received from a network. Bits from data streams at a logical level are placed into TFCs at a transport level based on the priority of the data streams and the TFCs available.
In one aspect, a plurality of applications provides a plurality of data streams to be allocated to a single stream. In another aspect, subscriber units provide a plurality of data streams to be allocated to a single stream of a base station. In still another embodiment, a plurality of base stations provide a plurality of data streams to be multiplexed by a multiplexer within a base station controller.
In one aspect, a subscriber unit comprises a memory, a plurality of applications residing in the memory, each application producing a data stream wherein each data stream comprises at least one block, and a multiplexer configured to receive each data stream and allocate bits from the plurality of data streams onto a single data stream.
In another aspect, a multiplexer is configured to receive each of a plurality of data streams and distribute bits from the plurality of data streams onto a single data stream based primarily on TFCs that meet TTI constraints and secondarily on the priority of the data streams.
In yet another aspect, a wireless communication system comprises a subscriber unit, a base station coupled to the subscriber unit, and a base station controller coupled to the base station. The subscriber unit includes a plurality of applications and a multiplexer, wherein each application produces a data stream as input to the multiplexer and each data stream comprises at least one bit. The multiplexer distributes bits from the data streams onto a single stream based on TFCs that meet TTI constraints.